This day-after-Thanksgiving, when many Americans are enjoying a day off and several others are at work goofing around on OSNews, we decided to ask you: what's your "killer app?" What's the one app you can't live without? Sound off in the comments - one app only!

Anyway, I disagree that Firefox is a Opera-copy. The 2 browsers have quite different approach to a lot of things. Esp surrounding functionality, Firefox doesen't have very much integrated, but you can use extentions to get more functionality. Opera have A LOT of stuff integrated but is more limited in terms of extendebility(you have Greasemonkey compatible JS-stuff and Widgets... that's the only thing I can think of.)

However a LOT of Firefox extensions hare inspired or even copied from Opera. But I don't really see the problem about that. Opera implemented Firefox' incremental search. It's just great that good features get into different software.

For the record: I'm not mistaken a Firefox user would have to install about 100 extensions to get all the functionality of Opera. This has both good and bad sides considering both browsers depending on you needs.

Also, something interesting: Firefox have probably 3-5 times as many users as Opera, but still Opera is mentioned as many times as Firefox here. This confirms that Opera users are very very happy with their browser, probably even more than most others. (Since Firefox-users are way more than Opera, logically one would expect a lot more people mentioning it.)